1. Field of the Invention
The invention is related to a wrench. To give more details, when installing or separating a fixing nut on or from the targeted objects, the invention could be used to install a fixing nut on multiple screw axes protruded from the hub in order to fix the tire wheel to the hub or to separate a fixing nut from the fixed screw axis. This invention is pertaining to a wrench of maximizing convenience by immediately recognizing the complete installation of a fixing nut based on the idle operation status of the operating gear, not based on the visual examination.
2. Background of the Related Art
The device is used to tighten or loosen a fixing nut or to fasten or loosen the nut fixed to the tire wheel hub of a vehicle. In general, in this case, a wrench is used. The applicant has been already granted a U.S. Pat. (No. 6,742,417) (hereafter ‘existing technology’) for a device of fastening or loosening a fixing nut with less energy in a prompt manner designed for female and elderly users.
The existing technology is as follows:
While the connecting part and the main socket are assembled, the main socket is assembled with the target nut to be loosened or tightened, and auxiliary socket is assembled with other nut.
Afterwards, when rotating the handle to make the operation axis spin, due to the strengthened spinning power of the transmission means including first transmission and second transmission, rotation is conducted to easily loosen or tighten the target nut.
Meanwhile, the torque spring installed to support the resilience between the gripping tube's inside wall and rod is compressed only to a certain level until the target nut is completely fastened.
To the contrary, the operating axis does not spin any more after the target nut is completely fastened. In this situation, if a force bigger than the repulsive power of the torque spring is applied to the handle for spinning, the torque spring is compressed to the maximum level, and the gripping tube's inside wall and the outside surface of the rod become the closest.
This work process requires the user to check the level of the torque spring compression visually through the opening at the end of the gripping tube in order to tighten the target nut. Therefore, users will experience lots of inconvenience in tightening the target nut.
In addition, when the target nut is completely fastened, the operating axis does not spin any more. If the torque spring is compressed to the maximum level by applying a force bigger than the repulsive power of the torque spring to the handle, it often happens that the end of the gripping tube does not have a consistent direction, and it is headed downward sometimes. In this case, the user finds it difficult to make a visual check.